Method and apparatus for increasing voltage in a charge pump used in a phase locked loop

Abstract

An apparatus and method of increasing the voltage of a charge pump (111) used in a synthesizer charge pump network (100). The invention enables a voltage boost network (123) to be connected to a charge pump (111) and utilizes a capacitor which is charged and discharged synchronously with the charge pump to allow the charge pump (111) to effectively operate at a higher voltage than ordinary supply (V2). The invention allows the synthesizer charge pump network (100) to be operated in a low voltage condition without providing switching of external voltages greater than supply thereby eliminating EMI and increasing operating efficiency.

What is claimed is: 
     
       1. A synthesizer charge pump network comprising: a synthesizer means for providing a range of first control signals;   a voltage controlled oscillator for producing a range of second control signals for controlling said synthesizer means and an output signal at a predetermined frequency;   a plurality of charge pump means connected to said voltage controlled oscillator for providing a plurality of current sources;   a voltage boost means serially connected between at least one of said plurality of charge pump means and a first predetermined supply voltage for increasing said first predetermined supply voltage, applied to said at least one of said plurality of charge pump means, to a second predetermined voltage;   a plurality of charge pump control means controlled by said range of first control signals, where at least one of said plurality of charge pump control means is connected to a respective one of said plurality of charge pump means and said voltage boost means for control information for said at least one of said plurality of charge pump means and said voltage boost means; and   wherein a single control signal generated by the synthesizer means is used for maintaining operation of both said voltage boost means and said plurality of charge pump control means in a synchronized manner and further wherein said voltage boost means is actuated by said at least one of said plurality of charge pump control means so as the actuation of said voltage boost means and said at least one of said plurality of charge pump means are substantially synchronized and further wherein said network operates using a limited duty cycle of said plurality of charge pump means to provide a non-steady state boost voltage from said voltage boost means.   
     
     
       2. A synthesizer charge pump network as in claim 1 wherein said range of first control signals include a first charge pump control means signal for controlling a first charge pump means and a second pump control means signal for controlling a second charge pump means. 
     
     
       3. A synthesizer charge pump network as in claim 1 further comprising a filter means connected to said voltage controlled oscillator for eliminating emissions emitted by said voltage controlled oscillator of a predetermined frequency. 
     
     
       4. A synthesizer charge pump network as in claim 1 wherein said voltage boost means comprises at least one capacitor for storing a predetermined voltage potential. 
     
     
       5. A method of increasing the operating voltage range of a synthesizer charge pump network, said synthesizer charge pump network including a phase locked loop having a plurality of current sources, the method comprises the steps of: supplying a first predetermined voltage to a voltage increasing network located within said synthesizer charge pump network, said voltage increasing network supplying voltage to at least one current source of said plurality of current sources;   controlling said voltage increasing network synchronously with said at least one current source with a single control signal from a synthesizer divider to increase the voltage supplied to said at least one current source to a second predetermined voltage;   charging at least one capacitor located with said voltage increasing network using said first predetermined voltage;   switching the charge within said at least one capacitor to said at least one current source to provide a non-steady state increase of said first predetermined voltage to said second predetermined voltage thereby increasing the performance of said phase locked loop; and   whereby said voltage increasing network improves the operating voltage range of said phase locked loop enabling it to operate in a voltage range above said network supply voltage.   
     
     
       6. A method of increasing the performance of a phase locked loop as in claim 5 wherein said at least one current source includes at least one transistor. 
     
     
       7. A synthesizer charge pump network comprising: a first charge pump controlled by a first control means and powered by a voltage supply for providing a first current source in a phase locked loop;   a second charge pump controlled by a second control means for providing a second current source in said phase locked loop;   a synthesizer for providing a plurality of control signals to said first control means and said second control means;   an oscillator connected to said first charge pump and said second charge pump for providing a radio frequency (RF) signal;   a storage network attached to said first control means and said first charge pump for storing a voltage potential of a predetermined value from said voltage supply; and   wherein said storage network is synchronously charged with said first charge pump and is actuated when said first charge pump is actuated using a single control signal generated by the synthesizer to increase the supply voltage applied to said first charge pump thereby increasing the efficiency of said phase locked loop in a low voltage condition and further wherein said synthesizer charge pump network operates using a limited duty cycle of said first charge pump and said second charge pump to provide a non-steady state boost voltage from said storage network.   
     
     
       8. A synthesizer charge pump network as in claim 7 further comprising a filter connected between said oscillator and said first charge pump and said second charge pump for removing unwanted emissions by said oscillator. 
     
     
       9. A synthesizer charge pump network as in claim 7 wherein said oscillator is a voltage controlled oscillator. 
     
     
       10. A synthesizer charge pump network as in claim 7 wherein said plurality of control signals includes a first control signal for controlling said first control means and a second control signal for controlling said second control means.